Bronchoscopy, which is the procedure by which the bronchial tree of a patient is visually inspected, is an important technique in the treatment of respiratory failure. However, until quite recently, the procedure frequently was not employed because of the accompanying risk of not being able to maintain adequate ventilation and oxygenation during the procedure. The relatively recent development of the fiberoptic bronchoscope which is flexible and of much smaller external diameter than the conventional bronchoscope has reduced the risks of inadequate ventilation and oxygenation and as a result made the procedure more popular. However, the present practice of introducing the fiberoptic bronchoscope into the bronchial tree of a patient via a conventional endotracheal tube is not without disadvantage. For example, during bronchofiberoscopy, if the bronchofiberscope is introduced through an endotracheal tube, the presence of the bronchofiberscope in the endotracheal tube creates a resistance to flow much higher than is normally encountered. Therefore there is every possibility that the patient may not be able to breathe adequately if awake or be ventilated adequately if under anesthesia or on a ventilator (in an intensive care situation).